Add reproduction steps

Signed-off-by: Brendan Dougherty <[email protected]>

examples/local/run_queries.go

@@ -0,0 +1,26 @@
+package main
+
+import (
+	"context"
+	"log"
+
+	_ "vitess.io/vitess/go/vt/vtctl/grpcvtctlclient"
+	_ "vitess.io/vitess/go/vt/vtgate/grpcvtgateconn"
+	"vitess.io/vitess/go/vt/vtgate/vtgateconn"
+)
+
+func main() {
+	ctx := context.Background()
+	conn, err := vtgateconn.Dial(ctx, "localhost:15991")
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer conn.Close()
+	session := conn.Session("things", nil)
+	for {
+		_, err := session.Execute(ctx, "SELECT * FROM things WHERE id = 'fooBARfooBARfooBARfooBARfooBAR'", nil)
+		if err != nil {
+			log.Fatal(err)
+		}
+	}
+}

examples/local/vtgate_unicode_vindex_memory_leak.md

@@ -0,0 +1,75 @@
+Setup
+======
+* Edit `go/vt/vtgate/vindexes/unicode.go` to not use a pool (just a single shared `pooledCollator` protected by a mutex)
+  This ensures that reproduction isn't impacted by the nondeterministic nature of sync.Pool, i.e. https://pkg.go.dev/sync#Pool
+  > Any item stored in the Pool may be removed automatically at any time without notification. If the Pool holds the only reference when this happens, the item might be deallocated.
+  
+* `SKIP_VTADMIN=true ./101_initial_cluster.sh`
+* Create a new sharded "things" keyspace:
+```bash
+source ../common/env.sh
+
+for i in 300 301 302; do
+	CELL=zone1 TABLET_UID=$i ../common/scripts/mysqlctl-up.sh
+	SHARD=-80 CELL=zone1 KEYSPACE=things TABLET_UID=$i ../common/scripts/vttablet-up.sh
+done
+
+for i in 400 401 402; do
+	CELL=zone1 TABLET_UID=$i ../common/scripts/mysqlctl-up.sh
+	SHARD=80- CELL=zone1 KEYSPACE=things TABLET_UID=$i ../common/scripts/vttablet-up.sh
+done
+
+# set the correct durability policy for the keyspace
+vtctldclient --server localhost:15999 SetKeyspaceDurabilityPolicy --durability-policy=semi_sync things || fail "Failed to set keyspace durability policy on the things keyspace"
+
+for shard in "-80" "80-"; do
+	# Wait for all the tablets to be up and registered in the topology server
+	# and for a primary tablet to be elected in the shard and become healthy/serving.
+	wait_for_healthy_shard things "${shard}" || exit 1
+done
+```
+* Create the VSchema:
+```bash
+vtctldclient ApplyVSchema --vschema '
+    {
+        "sharded": true,
+        "vindexes": {
+            "unicode_loose_md5": {
+                "type": "unicode_loose_md5"
+            }
+        },
+        "tables": {
+            "things": {
+                "column_vindexes": [
+                    {
+                        "column": "id",
+                        "name": "unicode_loose_md5"
+                    }
+                ]
+            }
+        }
+    }
+    ' things || fail "Failed to create vschema in sharded things keyspace"
+```
+
+* Create the SQL schema:
+```bash
+vtctldclient ApplySchema --sql '
+  create table if not exists things(
+    id varchar(255) not null,
+    primary key(id)
+  ) ENGINE=InnoDB;
+' things || fail "Failed to create tables in the things keyspace"
+```
+
+* Check vtgate memory use
+```
+cat /proc/$(cat /tmp/vtdataroot/tmp/vtgate.pid)/status | grep RSS
+```
+
+* Run lots of queries
+```bash
+go run run_queries.go
+```
+
+* Keep checking memory use